POSTN and asthma: In a post hoc analysis of the asthma group, there was a change in classification from ‘high periostin’ to ‘low periostin’, based on the 0800 and 1800 h periostin levels, utilizing the proposed cut point of 50 ng/mL in 1/16 participants (50.3 and 48.2 ng/mL at 0800 and 1800 h, respectively) (Additional file 1: Table S1).